Just under 4 per cent of those teaching in schools last January were classified as unqualified by the Government. This category included teachers trained outside of the EU, and certain other European counties; instructors who are employed when no qualified teacher is available; and certain types of trainees, including those on the Graduate and Registered Teacher programmes, plus Teach First participants.

In total, more than 10,000 of these unqualified teachers were employed in maintained secondary schools in January. The total would no doubt have been even greater if those employed in academies, who offer places to many Teach First trainees, were also included.

Even without the academies, London secondary schools accounted for some 20 per cent of the secondary school total of unqualified teachers. Two boroughs in the capital, both with selective secondary schools, accounted for nearly 300 such teachers. In one case, these teachers accounted for more than 10 per cent of the secondary teachers in the borough. Between them, the secondary schools in two London boroughs employed 100 more unqualified teachers than the total for all the local authorities in the North East of England.

Unqualified teachers are much less common in the primary sector, where there were only about 4,000 employed in January, of whom nearly half were working in London.

John Howson is a director of Education Data Surveys, part of TSL Education.